The present invention relates generally to thermal radiators, and more particularly to an improved thermal radiation device suitable for use in electrical heating apparatus such as toasters and ovens.
Commercial-type toasters and baking ovens are often constructed with a moving grill or conveyor on which an article such as food or pottery is placed and passed through a large chamber between rods of continuously energized electric heating coils disposed over and under the conveyor. Their operation and maintenance expenditures are of continuing concern, especially with rising costs of energy and labor. The thermal (infrared) radiation efficiency is improved with metal reflectors spaced opposite of the far sides of the heating elements to reflect any outwardly radiating thermal energy toward the article thereby increasing the watt density (watts per square inch) or heat available at the surface of the article for the same rating. To increase heating effectiveness even further, prior art systems simply use heating elements of higher watt ratings. Reflectors located under the conveyor also become less effective because debris, such as bread crumbs, collect on the reflecting surfaces. Instead of reflecting the radiant energy, it is absorbed by the debris and conducted into the reflector and supporting structure. Consequently, it is periodically necessary to remove these reflectors for cleaning out accumulated debris, especially before they begin to smoke and burn as well as permanently mar the preferably bright finish of the reflector. In commercial heating apparatus, this entails costly production shutdowns and added labor for removing and cleaning or replacing the reflectors.